Cardiomyogenesis of periodontal ligament-derived stem cells by dynamic tensile strain.

Cellular therapies for the treatment of myocardial infarction have proven to be an invaluable tool in recent years and provide encouraging evidence for the possibility to restore normal heart function. However, questions still remain as to the optimal cell source, pre-conditioning methods and delivery techniques for such an application. This study explores the use of a population of stem cells arising from the neural crest and isolated from adult human periodontal ligament along with short-term mechanical strain as an inducer of cardiomyogenesis and possibly pre-conditioning stimulus for cellular cardiomyoplasty. Cells were subjected to a short-term dynamic mechanical tension in our custom-built bioreactor and analyzed for cardiomyogenic commitment. Mechanical strain elicited a cardiomyogenic response from the cells following just 2 h of stimulation. Mechanical strain activated and translocated cardiac-specific transcription factors GATA4, MEF2C and Nkx2.5, and induced expression of the sarcomeric actin and cardiac troponin T proteins. Mechanical strain induced production of significantly higher levels of nitric oxide when compared to static controls. Elimination of elevated ROS levels by free radical scavengers completely abolished the cardiomyogenic response of the cells. MicroRNA profile changes in stretched cells were detected for 39 miRNAs with 16 of the differentially expressed miRNAs related to heart development. The use of stem cells in combination with mechanical strain prior to their delivery in vivo may pose a valuable alternative for the treatment of myocardial infarction and merits further exploration for its capacity to augment the already observed beneficial effects of cellular therapies.

The Effect of Prostaglandin Analogue Bimatoprost on Thyroid-Associated Orbitopathy.

Purpose: We characterize the effect of bimatoprost on orbital adipose tissue in thyroid-associated orbitopathy (TAO) with clinicopathologic correlation. Methods: Orbital adipose-derived stem cells (OASCs) from types 1 and 2 TAO and control patients with and without exposure to 1 µm bimatoprost were examined via immunohistochemistry, RT-PCR, and Western blot for cell viability, migration capacity, lipid content, adipocyte morphology, mitochondrial content, and levels of adipogenic markers. A retrospective chart review was performed for clinicopathologic correlation. In mice, optical coherence tomography and pattern electroretinography were performed at baseline and at 1 month following a retrobulbar injection of bimatoprost, followed by orbital exenteration for histopathologic examination. Results: Types 1 and 2 TAO-derived cells had a significantly higher migration capacity and lipid content than those of healthy controls. With the addition of bimatoprost, types 1 and 2 TAO and control adipocytes exhibited a significant decrease in lipid content with morphologic transformation into smaller and multilocular lipid droplets, and an increase in mitochondrial load and UCP-1 expression consistent with an increase in brown adipose tissue turnover. Retrobulbar injection of bimatoprost in mice did not alter the gross morphology, retinal thickness, or ganglion cell function in vivo. Conclusions: Bimatoprost inhibits adipogenesis in OASCs and upregulates pathways involved in the browning of adipocytes. Furthermore, retrobulbar injection of bimatoprost is tolerated without immediate adverse effects in mice. Our results suggest a potential future application of prostaglandin analogues in the treatment of TAO.